RF Transmit Path With Shared IQ Conversion for mmWave Radios
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Solution Overview
Problem
Conventional RF-sampling data converters are inefficient when used for millimeter wave applications, as they require separate converters for I and Q channels, leading to resource wastage and reduced antenna support.
Innovation Solution
A semiconductor device with a flexible transmit path that includes digital and analog mixer circuitry, allowing for efficient upconversion and downconversion of RF signals, enabling the generation of IQ output signal pairs with reduced resource usage by shifting signal frequencies by FS/4 Hz, which simplifies filtering and relaxes requirements for additional filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate converters are used for I and Q channels in millimeter wave applications, then the required IQ pair functionality is achieved, but the number of supported antennas is halved and valuable resources are wasted
Solution Approach 1:
The patent implements a single RF-sampling data converter that can function as both an I-channel and Q-channel converter by utilizing complex baseband signals and digital mixing. The converter is configured to receive complex baseband signals containing both I and Q components, perform digital mixing to separate them, and output both I and Q channel signals sequentially or simultaneously, thereby eliminating the need for two separate converters and doubling the number of supported antennas.
Solution Approach 2:
The patent employs dynamic switching and time-division multiplexing techniques where the single converter alternates between I and Q channel operations. The system dynamically configures the converter's operation mode based on whether it needs to process I or Q signals at any given moment, using digital mixing and switching circuitry to route signals appropriately, thus achieving flexible resource utilization with a single converter.
2Reliability
If RF-sampling converters optimized for direct RF conversion are used for millimeter wave applications requiring external mixing, then the converter's primary function is maintained, but half of the converter resources are wasted
Solution Approach 1:
The patent extends the functionality of RF-sampling converters designed for direct RF conversion to also support external mixing architectures. By incorporating complex baseband signal processing and digital mixing capabilities, the converter can operate in both direct conversion mode and external mixing mode, maintaining its primary RF conversion reliability while enabling dual-channel I/Q operation that fully utilizes the converter's resources.
3Quantity of substance
If a single converter is used for both I and Q channels, then resource wastage is eliminated, but the device complexity increases due to digital mixing requirements
Solution Approach 1:
The patent replaces what would traditionally require separate physical converter hardware with digital signal processing techniques. Digital mixing and switching circuitry are used to separate I and Q channels from a single converter output, substituting the need for duplicate hardware with software-controlled digital processing, thereby reducing overall device complexity despite adding digital processing functions.
Data Source
AI summary
A semiconductor device comprising at least one transmit path is provided. The transmit path comprises an input node for receiving a digital baseband signal. Further, the transmit path comprises digital mixer circuitry coupled to the input node and configured to generate an upconverted digital baseband signal by upconverting a frequency of the digital baseband signal. Additionally, the transmit path comprises Digital-to-Analog Converter (DAC) circuitry coupled to the digital mixer circuitry and configured to generate an analog radio frequency signal based on the upconverted digital baseband signal. The transmit path comprises first analog mixer circuitry coupleable to an output of the DAC circuitry, and second analog mixer circuitry coupleable to the output of the DAC circuitry. Further, the transmit path comprises a first output node coupleable to an output of the first analog mixer circuitry, and a second output node coupleable to an output of the second analog mixer circuitry.